The present invention relates, in general, to lubricants for use in shaving, and more particularly to a new class of hair shaving lubricants, herein called xe2x80x9cdifferential lubricantsxe2x80x9d (or xe2x80x9cdi-lubricantsxe2x80x9d) which only highly lubricate skin, but not hair shafts.
Prior art lubricated hair shaving is based on the assumption that skin, hair, and razors should be highly lubricated, and an entire shaving lubricant industry has been built around the reduction of skin damage and longevity between shaves. The main purpose of the entire global shaving lubricant industry is to achieve the closest shave without pain or discomfort. However, the underlying physics principles of shaving hair has, until now, remained flawed.
Lubricated hair shaving is believed to predate recorded history. To everyone who has attempted or experienced razor shaving without a lubricant, it becomes obvious that severe skin damage always occurs. Even with lubrication, nicks, cuts, razor burn, rough skin, chemical irritation, and the like, are common, and skin lubrication is absolutely necessary for very close razor shaving. It is no surprise, then, that the shaving lubricant industry is a multibillion dollar industry. Ever since the original discovery of lubricated shaving, the need for increasing general lubrication of skin, hair, and razor has been promoted.
The technological art of lubricated hair shaving has been improved, with the introduction of sharper razor blades and better lubricants, to such degrees that one no longer thinks of shaving hair at the skin level, but below the skin level. Microscopic hair length differences smaller than 0.001 inch can easily be discerned. Therefore, to further improve the art of mechanical shaving, microscopic laws of physics about hair, skin and, razors must be elaborated. Lubricated shaving centers on three objectivesxe2x80x94closeness and longevity of each shave, minimizing skin damage, and minimizing chemical toxicity.
Lubricated shaving continues to be favored over electric dry razor shaving for several reasons. Wet razor shaving permits far higher applied skin pressure (force per unit area) and thus, it forces hair shafts farther upward from the dermal tissues just before being cut. The inherent advantages derived from the much higher skin pressures of wet shaving also demand high lubrication to prevent skin damage. Therefor, prior art shaving lubricants seek to achieve the highest skin lubricating properties in order to permit application of the greatest skin pressure and hence, the closest shaves. That approach is reasonable, until a closer microscopic examination of the physics of cutting hair is conducted. Prior art lubricants seek to provide maximum skin lubrication without regard to the fact that microscopic hair lubrication occurs at the same time. However, if hair shafts and razor cutting edges are highly lubricated like skin, undesirable microscopic slippage takes place just before the microscopic cut begins on each hair shaft. That same lubricated microscopic slippage continues as the razor slices through each hair shaft. Such lubricated slippage on hair shafts effectively lengthens the cut hair by several thousandths of an inch, which is equivalent to almost one days"" growth. As minute as a few thousandths of an inch might seem, in reality, it represents a large percentage of daily hair growth, as well as a large measure of the over all quality of shaving. Hair grows at varying rates, approximating 1-3 hair-diameters per day. Typical male facial hair is about 0.005-0.008 inch in diameter, and grows about 0.005 to 0.010 inch in length per day. Female leg hair is typically finer and grows more slowly. If hair protrudes just 0.001 to 0.002 inches above skin level, it can easily be detected by human touch. By the time hair has grown 0.003 to 0.004 inches above skin level, hair stubble is quite visible and a shave is warranted. Hence, the closer the shave and the farther below the skin level a shave can be achieved, the longer the shave will last before the hair is detected again.
For example, assume that a single 0.007 inch diameter hair shaft is theoretically cut off perfectly perpendicular to the shaft, and 0.004 inches below the skin surface. One day later, at a 0.008 inch/day growth rate, that hair will have grown 0.008 inches and will again protrude 0.004 inches above the skin level. Next, visualize a highly lubricated 0.007 inch diameter hair being shaved. Instead of the hair being ideally cut straight across from the initial razor contact point, instead, the lubricated razor will microscopically slide up the lubricated hair shaft before it begins cutting through the hair. Then, prior art lubricants continue to lubricate the actual cutting action as the razor slides through the hair shaft, producing an upward motion and a sloped, or tapered, hair end. The final result of lubricating hair is a tapered cut, typically at less than 60 degrees instead of the ideal 90 degree perpendicular hair shaft cut. A typical 0.007 inch diameter hair shaft cut at just 45 degrees will be sharp and pointed and about 0.003 to 0.004 inches longer than one perpendicularly cut at the ideal 90 degrees (see FIG. 1). In other words, a lubricated hair can not be as bluntly cut because lubricants allow slippage in two waysxe2x80x94slippage on the initial contact before cutting and also slippage during cutting. The resulting sharp pointed hair ends protrude upwardly an amount equal, in many cases, to more than a half day""s growth as compared to an ideal blunt cut hair shaft which may be several thousandths of an inch shorter. Clearly, therefore, hair shafts should be microscopically totally unlubricated for the closest shave. And yet, skin must be lubricated for the absolute minimum friction. These two diametrically opposed requirements (high skin lubrication and zero hair lubrication) seem to be impossible to obtain from a single lubricant or even from a combination of lubricants. Nevertheless, as will be shown, the present invention does indeed simultaneously exhibit both of these diametrically opposing properties.
Prior art shaving lubricants not only make the error of lubricating skin and hair, but they also are much more toxic than most people perceive. The term xe2x80x9cGenerally regarded as safexe2x80x9d (or xe2x80x9cGRASxe2x80x9d) does not mean xe2x80x9cNon toxicxe2x80x9d. The popular presumption that xe2x80x9cGRASxe2x80x9d means xe2x80x9csafe if not ingestedxe2x80x9d is incorrect. As used in the present disclosure, xe2x80x9cToxicxe2x80x9d is defined as any amount of any substance entering the body, through any means, which stresses bodily organs or functions or which do not nutritionally support normal healthy bodily processes. This broadened definition of toxicity does not embrace GRAS principles, which are directed more towards xe2x80x9ctoxic limits of endurancexe2x80x9d.
Sadly, there are almost no government regulations on cosmetic shaving lubricants, yet many toxic chemicals are present in virtually every commercial shaving lubricant. The popular belief is that if these toxic shaving substances are not ingested, they are safe, but that belief is unwarranted. Exhaustive research conducted by a pharmaceutical company, Innovative Dermal Applications, GmbH in Germany, has only recently revealed some of the limitations and physics of how skin protects against microorganisms and toxic chemicals. For example, it is now known that skin is an excellent biological barrier because skin""s outermost horny layer (the stratum corneum) composes only 10% of the skin""s thickness, but contributes about 80% to the permeability barrier. The horny layer is a microporous barrier, which only allows passage of less than 1 nanometer diameter molecules. That is, 1 nanometer molecules will freely pass through healthy dry skin. Most molecules of less than a few thousand molecular weight (MW), such as pharmaceutical drugs and most toxins, are much smaller than 1 nanometer in physical size. Therefore, they readily pass directly through skin directly into the capillary blood stream or via the lymphatic system into the blood stream. However, when skin is exposed to hot water and becomes fully hydrated, the crevasses in the micro-porous horny layer widen to as much as 20-100 nanometers. Usually, shaving involves hot water skin hydration and under these conditions is much more porous and can transport even extremely large molecular toxins (compounds in excess of 1,000,000 MW) directly into the body. Unfortunately, generally available commercial shaving lubricants contain significant quantities of known toxins of relatively low molecular weight which not only can, but do enter the human body during every shave. Toxic dosage is directly proportional to the exposed skin area (and the type of skin as well). Large areas, like female legs for example, are regularly and frequently exposed to 15 to 20 times that of men""s faces. Most women are therefore exposed to much higher toxic loading than men.
Colorant dyes, fragrances, petroleum oils, synthetic oils, and numerous chemical additives are present in most shaving lubricants, and frequent exposures can be very deleterious to human health. The most popular pressurized commercial shaving foams and gels contain innumerable low and medium molecular weight toxins such as highly flammable pentane, with a toxic exposure limit of only 600 PPM, triethanolamine (damages liver and kidneys), menthol (an irreversible irritant/allergen), colorant dyes, synthetic lubricants, fragrances, and countless other similar toxic chemicals, all of which pass through skin to challenge vital organs. These chemicals and gases are usually used in small closed rooms where they are absorbed through wet skin, and are breathed and rebreathed. Aside from all these chemical threats, the pressurized containers themselves may also rocket and explode under heat or fire. Most of these warnings are published and publicly available in the commercial shaving lubricant""s product Material Safety Data Sheets (MSDS). What is not clearly spelled out is how easily they enter the body through the skin each time they are used.
Several prior art shaving lubricant patents (not di-lubricants) serve to reinforce this point. One patent teaches the use of moderate concentrations (0.5% to 4% by weight) of water soluble, lubricating polymers such as polyacrylamide, but it only observes the obvious and well known high lubricity characteristics of polyacrylamide, like all prior art shaving lubricant inventions; it totally disregarded potentially lethal toxicity and was oblivious to the existence or the importance of di-lubricity. Another patent proposed the blending of soaps and detergents plus small quantities of polyacrylamide to form hand lathering lubricants did not mention that mixing hydrated polyacrylamide with other soap and detergent lubricants of much lower lubricating properties causes the composite mixture to largely assume the lower lubricating properties of the smaller molecular weight soaps and detergents. The much higher lubricating properties of hydrated polyacrylamide are mostly lost in the proposed hand lathering mixture. What is needed is maximum skin lubricity. Most importantly, the high concentrations of the soaps and detergents (all of quite low molecular weight) all cause skin, and especially hair, to be highly lubricated, when it will be shown in the present invention, that hair should not be lubricated at all. Furthermore, the patent proposes adding polyacrylamide as small as 500,000 molecular weight, without recognizing that such low molecular weight acrylamide polymers (500,000) cannot be made without also introducing dangerously high concentrations of unpolymerized highly toxic acrylamide monomers (several percent), as well as smaller polymer chains (such as 50,000 MW) polymer chains. Both the toxic unpolymerized acrylamide monomers as well as the smaller chains of polyacrylamide can, upon application to the skin, migrate through the skin into the body. Skin porosity characteristics and toxicity was of no importance in that invention. In a similar fashion, another polyacrylamide-containing patent proposed adding small amounts of polyacrylamide to a wide variety of high concentrations of other lubricants to produce aerosol foaming shaving lubricants. As previously pointed out, the addition of lubricants of lower lubricity to one of higher lubricity significantly reduces the over-all lubricity of the highest lubricant. In addition, the patent also aims exclusively at general lubrication of skin and hair without recognizing the fundamental importance of not lubricating hair.
There is a large and rapidly growing body of scientific evidence that strongly supports the thesis that every exposure to small doses of known toxins, which are present in literally hundreds of consumer products, produces, at the very least, a compromised immune system and stressed vital organs. Although most shaving lubricant manufacturers publish their products as GRAS products, when the toxicity of those products is combined with the nearly endless list of other toxic products (particularly cosmetics) to which people are regularly exposed, the GRAS principle is greatly diminished. Diminished health is a subtle but real result of these multiple toxic exposures. Shaving lubricants should be especially nontoxic because they are so regularly used and because they cover such high skin surface areas, under the most vulnerable hydrated conditions. Unfortunately, in order to obtain the desired lubricating properties, manufacturers have only been able to achieve moderate toxicity. As will be shown, the present invention achieves this important, essentially zero toxicity objective, without compromising the new property called di-lubricity.
Therefore, the objectives of the present invention are: 1). To greatly minimize shaving toxicity through the use of unusually large lubricating molecules which can not penetrate skin; 2). To more highly lubricate skin and further protect skin from damage, both during and after shaving; 3). To simultaneously minimize hair shaft lubrication while maximizing hair shaft hydration; 4). To cut hair ends more perpendicularly, which produces considerably closer shaves; and 5). To significantly extend the time periods between shaving.
Briefly, the present invention is directed to a new and unique lubrication for use in shaving, wherein a di-lubricant is applied to the skin in the usual way, but only the skin is lubricated; the hair itself is not be lubricated. The present invention represents a quantum departure from the old universal lubrication concept. Very large water-molecule lubricants, as formulated herein, are used, and these not only provide the desired lubrication of the skin, but not the hair, they also exhibit unusually low toxicity, which make them useful for many other general medical lubricant applications.
Di-lubrication provides a high degree of slippage between the skin and a razor, to permit the application of pressure to cut hair below the skin level without damage to the skin. In addition, since it does not lubricate the hair, it ensures zero micro-slippage, and therefore an instant grip of the razor upon initial microscopic contact of the razor edge with each hair shaft, and this produces perpendicularly-cut hair rather than tapered cut hair shafts. The result is considerably closer and significantly longer lasting shaves, up to almost twice that of prior art of shaving lubricants, while at the same time maximizing skin hydroplaning for minimal skin damage. Since skin is a highly porous organ and is a direct path for toxins to enter the body, the preferred embodiment of the present invention also achieves extremely low toxicity through the use of extra large lubricant molecular structures, composed of essentially water, which cannot penetrate the microprobes of skin.
In one preferred embodiment of an ideal di-lubricant formulation, unusually small concentrations of fully hydrated, extra-long-chain, purified flocculant polyacrylamide molecules are suspended like soft microscopic ball bearings in water. Under these conditions of ultra low concentrations, polyacrylamide transforms from a known excellent lubricant into a high performance differential lubricant with very unexpected new hair shaving properties. The preferred di-lubricant essentially consists of highly nontoxic gigantic polyacrylamide water-spheroids of 99.9+% water; which are designed to act like soft ball bearings between razor and skin, but which molecularly self-destruct when subjected to the considerably higher mechanical pressures (force per unit area) encountered between razors and relatively hard hair shafts, thus producing near zero lubrication on each hair shaft. When these two distinctly opposite (lubricant/non-lubricant) physical properties are combined with the low viscosity of water, razors freely slide and hydroplane over skin, but exhibit no microscopic slippage on hair. High shaving forces can be applied without razor burns, skin cutting or nickingxe2x80x94allowing even closer shaves than prior art lubricants. The lack of an effective lubricant on the hair results in near zeromicroscopic slippage of the razor on the hair shafts and causes the hair to be cut perpendicularly, and thus considerably shorter, than was possible with the sharp tapered hair shaft cuts of the prior art. Less damaged skin, shorter hair cutting, and greatly reduced toxicity are the unexpected results of the present invention""s unique di-lubrication formulations. Finally, it is important to reemphasize that di-lubrication represents a distinct and radical departure from all prior art general purpose lubricated shaving, and that many other di-lubricant formulations are possiblexe2x80x94none of which materially depart from the scope and intent of the present invention.